Electro-magnetic relay



Dec. 8, 1959 SEELE 2,916,580

ELECTRO-MAGNETIC RELAY Original Filed Aug. 27, 1956 IN VEN TOR. HARUL 0 4. 5EEL ATTOP/VEY States Patent 'Ofifice 2,916,580 Patented Dec. 8, 1959 Divided and this application July 29, 1957, Serial No.

' '2 Claims. (Cl. 200-87) Thisiinvention relates'to an electro magnetic switch construction and is a division of my pending application, Serial No; 606,258jfi1ed August 27, 1956. I An object of thepresent invention is to provide an electro-m'agne'tic switch 'or relay that embodies novel and improved means to mechanically vary a biasing force that acts counteror opposed to the magnetic flux that operates the switch or relay.

Another object of the invention is to provide a switch of the character above referred to that is provided with novel fiat-spring ineans that produces a biasing force and whichis con troll edto vary such force.

i i qtgqfthe invention isto provide a relay of the character referred to that isextremely sensitive to resistance introduced into the electric current passing through the coil thereof,,thereby providing a switch or relay that moves 'betweencireuit-open and circuit-closed positions inf'iesponse to small changes in the potential across the relay coil.

The invention also has for its objects to provide such means that are positive in operation, convenient in use, easily installed in a working position and easily disconnected therefrom, economical of manufacture, relatively simple, and of general superiority and serviceability.

The invention also comprises novel details of construction and novel combinations and arrangements of parts, which will more fully appear in the course of the following description. However, the drawing merely shows and the following description merely describes, one embodiment of the present invention, which is given by way of illustration or example only.

In the drawing, like reference characters designate similar parts in the several views.

Fig. 1 is an end elevational view of a resistance-sensitive relay according to the present invention.

Fig. 2 is a side elevational view thereof.

Fig. 3 is a perspective view of a spring member used in the relay construction to normally bias the relay to circuit-open position.

The present resistance-sensitive relay comprises, generally, a frame 5 mounting an electro-magnetic coil 6 and provided with a movable magnetic armature 7, a switch 8 controlled by said armature, a spring member 9 interconnecting the frame and armature and normally biasing the latter to close switch 8, and means 10 to mechanically vary the biasing force of the member 9 to vary the sensitivity of response to switch-controlling movement of the armature according to the degree of potential in the coil 6.

The frame 5 is shown as G- or U-shaped, having opposed parallel arms 11 and 12 connected by a web 13. In this case, the arm 11 is connected to the spring member 9 and carries the tension-varying means 10, and the arm 12 carries one terminal of switch 8. The coil 6 is housed in the frame and is here shown with its fixed core 14 extending toward the open end of the frame between the frame arms 11 and 12. The armature 7 is shown as disposed across the open end of the frame and in pivotal engagement, at 15, with the end of said arm 11. Normally, said armature has flatwise engagement with the projecting end or pole shoe of the core 14 when the potential in the coil 6 is of such degree as to cause the armature to be attracted toward the core to the pole of the coil 6.

The spring member 9 is shown as made of flat-spring material and is provided with a flat portion 16 that is in fiatwise connection with the frame arm 11, a flat deflectable portion 17, generally normal to the plane of portion 16 and in flatwise connection with the armature 7, and a flat tongue portion 18 in general parallelism with the portion 16 and disposed between the frame arm 11 and coil 6.

As can be seen from Fig. 3, portion 18 may comprise a sheared-out center part of portion 16. By bending portion 1 8're1a tive to portion 17, along a bend line 19, and bending portion 16 relative to portion 17, along curved bends 20 on either end of the bend line 19 but ofiset relative thereto, an integral spring member is provided that enables varying of the tension between portions 16 and 17 by varying the deflection of portion 18 relative to bothp'ortion 16 and theframe arm 11. Thus, it will be ele'arjthat by deflecting portion 18, which is in the form of a spring arm, the armature 7 is deflected in a direction awayfrorn the normal position shown. The degree of bias holding said; armature thus deflected may be produced according to the deflection of arm 18. In other words, if:th e deflection of the armature is arrested, as by astop, andithe adjusting deflection of arm 18 is continued to cause it to bend relative to the armature, the force necessary to move the armature back to its initial position will be commensurate with the bias on said arm 18.

The mentioned switch 8 is shown as a terminal or contact 21 carried on a bracket 22 afiixed to the arm 12 of frame 5 and, in this instance, insulated from said arm by dielectric insulation 23, and a second terminal or contact 24 on the armature or on the portion 17 of spring member 9. Said contacts are opposed and normally engaged to place the bracket 22 and the frame 5, armature 7 or member 9, in electrical contact, the member 9, as above described, being normally so biased as to provide such electrical contact.

The means 10 is shown as a threaded adjusting member 25, engaged in threads 26 in frame arm 11 or in threads in both said arm and in the opening 27 of portion 16 of spring 9. The member 25 is so directed as to engage spring arm 18 and to impinge thereon, as shown. Thus, by rotationally adjusting member 25, the pressure on arm 18 may be eased off or increased, as desired, thereby changing the biasing force holding contacts 21 and 24 engaged.

The electro-magnetic force of coil 6, as manifested in core 14, constitutes an attraction that tends to draw the armature to the position shownin engagement with the magnet core. It will be clear that a greater potential across coil 6 is required to so attract armature 7 and open the switch contacts 21 and 24 if the arm 18 is under considerable flexure or tension, and that commensurately less potential is required under conditions where arm 18 is under lesser tension. Such potential may be varied by a change in the electrical resistance of the circuit supplying coil 6.

The member 9 may be varied in a minor way by so proportioning the portion 16 that member 25 will pass through the opening 28 that is left in said portion 16 when the arm 17 is sheared therefrom.

The arrangement of the switch may be reversed, opening under bias of the member 9 and closing when the armature is attracted. Also, the relay may have two switches controlled by the movement of the armature, one I opening and the other closing. In other words, a normally-closed switch may be opened when the biasing force of member 9 is overcome by magnetic force and the other switch closed, and vice versa.

While the foregoing has illustrated and described What I now contemplate to be the best mode of carrying out my invention, the construction is, of course, subject to modification without departing from the spirit and scope of my invention, Therefore, I do not desire to restrict the invention to the particular form of construction illustrated and described, but to cover all modifications that may fall within the scope of the appended claims.

Having thus described my invention, what I claim and desire to secure by Letters Patent is:

1. A sensitive electromagnetic relay comprising in combination, an electromagnet coil frame in U shape having opposed first and second parallel arms integral with a connecting web to leave an open end, an electromagnet core having an end against said connecting web and a free end forming a pole, an electromagnet armature of such length as to fit within the open end of said frame with only a small air gap, a switch member comprising sheet material in bent form with a transverse bend line having a portion in flatwise connection with the first frame arm on one side of the bend line and a freely deflectable portion on the other side of the bend line in flatwise connection with the armature lying across and in front of said magnetic pole subject to magnetic attraction thereof, a movable contact carried by the deflectable switch member portion, a stationary contact fixedly secured opposite said movable contact for operative relation therewith, the deflectable switch member portion having two limit positions in one of which said contacts are electrically connected and in the other disconnected, the magnetic attraction of said pole serving to move the armature and deflectable switch member portion from one limit position to the other, said switch member having a tongue portion integral with the deflectable portion substantially parallel to the flatwise connected portion lying on the opposite side of the bend line from said deflectable portion, and adjustable means for applying pressure to said tongue portion on the surface of the sheet material thereof opposite to the surface of the sheet material which in the deflectable portion thereof lies toward said coil pole for biasing the said switch member defiectable portion away from said pole.

2. In an electromagnetic device having an electromagnetic coil, an electromagnet frame arm extending the length of the coil to form a magnetic return path therefor and a movable armature, an armature biasing unit for compact assembly with the device having integral mutually normal portions composed of resilient bendable material, one of said portions extending along a portion of the length of the frame arm, being secured flatwise thereto, the other of said portions extending along the armature secured thereto fiatwise, and a spring arm integrally connected to the portion of the unit secured to the armature, but extending parallel to the frame arm along the coil, and having means for setting the position of the spring arm in relation to the frame for biasing the spring arm.

References Cited in the file of this patent UNITED STATES PATENTS 1,103,530 Newburn July 14, 1914 1,206,699 Harthan Nov. 28, 1916 2,351,448 Neuner June 13, 1944 2,487,372 Rackley Nov. 8, 1949 2,509,724 Cibie May 30, 1950 2,528,756 Kaser Nov. 7, 1950 FOREIGN PATENTS I 820,751 Germany Nov. 12, 1951 

